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Cannot connect through serial port https://www.8devices.com/community/viewtopic.php?f=1&t=953 |
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Author: | ngoncalves [ 03 Jul 2016, 18:40 ] |
Post subject: | Re: Cannot connect through serial port |
An update on what I have done so far: 1. the USB to Serial cable is crossed, I was wrong in my initial post 2. looking at the schematics of Carambola, there is a 3.3V <-> 5V level shifter on the serial port so this is not a voltage problem 3. I am 99,99% sure the board is working. When I connect an ethernet cable between its eth0 port and my PC (where I am running a DHCP server) I see a DHCP lease shortly after boot and I can ping that address Playing with different combinations of baudrate, data size, stop bits and parity I always get weird chars, so I thought it could be a problem of charset encoding. The boards are designed by a company in Estonia, maybe they are using cyrilic or something specific to that region. So I opened the serial port with 8N1 and 115200 baud/s, and captured its output to a file after pressing the reset button on Carambola. Then I tried opening that file with different encodings, without luck. Always giberish. Now I am thinking I might be reading from the wrong serial port. Looking at the schematics, COM1 is connected to the DB9 connector. Should I cut the traces and solder J10 and J9 so that I have COM0 instead ? |
Author: | gedass [ 04 Jul 2016, 07:03 ] |
Post subject: | Re: Cannot connect through serial port |
Hi, do you have breakout board schematics ? |
Author: | ngoncalves [ 04 Jul 2016, 10:05 ] |
Post subject: | Re: Cannot connect through serial port |
Hi, I got the dev board schematics from here: http://www.8devices.com/media/products/ ... ematic.pdf I assume they are correct. In the meanwhile, I am going to try with a different USB to serial cable. The one I have right now was hacked together from old parts and might not be suitable for 115200 baud/s. |
Author: | gedass [ 04 Jul 2016, 10:35 ] |
Post subject: | Re: Cannot connect through serial port |
Ok but this is original board developed by 8devices company not Estonian company. Are you using serial cable USB <-> DB9 or USB <-> 3.3V TTL ? Maybe something wrong with your USB converter cable ? Try another converter cable. Firmware original from 8devices ? |
Author: | ngoncalves [ 04 Jul 2016, 12:18 ] |
Post subject: | Re: Cannot connect through serial port |
I am using a USB <-> DB9 cable, but self-made and unshielded. It might be picking up noise. The board firmware was not modified. I bought the board a couple of years ago but never got the time to play with it. And I am sorry for confusing Estonia and Lithuania. I am a bit of an ignorant when it comes to geography and history. |
Author: | gedass [ 04 Jul 2016, 14:02 ] |
Post subject: | Re: Cannot connect through serial port |
Author: | ngoncalves [ 05 Jul 2016, 17:15 ] |
Post subject: | Re: Cannot connect through serial port |
Yup, it was the serial cable. Tried today with a proper, shielded cable, and it all worked fine. Thanks for your patient and time. |
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